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BEIJING, Oct 26 (Reuters) - China on Sunday began blocking the Yellow River
-- known as China's sorrow for its catastrophic floods throughout history
that have claimed millions of lives. The $4.17 billion water control project
in central Henan province is China's largest after the huge Three Gorges
dam, for which the work on diverting the mighty Yangtze river is due to
begin later this week.
The Xiaolangdi dam project on the Yellow River is among the most technically
complicated that China has ever undertaken, involving an intricate network
of tunnels threading through its banks. The blocking of the river began
when six trucks emptied their loads into the river and the task is expected
to take 42 hours to complete with Chinese and foreign engineers and labourers
working round the clock.
Work will then begin on the 154-metre (500-ft) high earth-filled dam, the
Xinhua news agency said. The project will control 93 percent of the river's
drainage area and be able to handle huge floods that may occur every 1,000
years, the Xinhua news agency said.
The World Bank is supplying a $1.0 billion loan for the project that will
enable dam operators to regulate the Yellow River's notoriously fitful
flow and another $109 million will come from foreign commercial credits.
The dam has a complex web of 16 tunnels burrowing through the river's left
bank and these will be used to regulate its huge silt load and erratic
water flow, fluctuating between a dawdling 1,500 cubic metres (53,000 cubic
ft) per second and a raging 16,000 cubic metres (565,000 cubic ft) per
second. The complex tunnel system has made the project the largest and
most complex of its kind in the world, Xinhua quoted Lin Xiushan, president
of the Survey, Planning, Design and Research Institute of the Yellow River
Conservation Commission, as saying.
The river's floods have killed more than 800,000 in the last five decades.
The river has overflowed its bank more than 1,500 times in the last 2,000
years and has seen 26 major changes in its course that have killed millions
more. Beijing spends $1.2 billion each decade to shore up the banks of
a river that rises 10 cm (four inches) a year and in many places looms
perilously over cities that lie under the shadow of the dikes that hold
it in.
The flow of the river was regarded as suitable for damming and Xinhua quoted
officials as saying that the flow on Sunday was even lower than the required
standard, making Sunday's work much easier. Some 40,000 people living the
area have been resettled to make way for a 12.5-billion-cubic-metre (441
billion-cubic-ft) reservoir behind that dam that is to serve as a catch
basin for the silt and will be capable of holding 7.5 billion cubic metres
(265 billion cubic ft) of sediment before it finally fills up after about
30 years, officials have said.
Next Saturday, Chinese engineers are to begin the huge task of diverting
the Yangtze river to allow them to build the world's biggest water control
project.
REUTER
黄河の１２５億トンの大ダム，Xiaolangdi dam project の河川切り替え工事が，４８時間をかけて行うことになり，昨日１０月２６日，開始された，と言うニュースです。黄河の開発計画については，既に資料も揃えているのですが，まだ解説するところまで言っていません。出来るだけ早くこのＨＰにも載せる積もりでいました，少し待って下さい。
しかし，世銀が１０億ドルも融資しているのですね。どうも公的融資が片手落ち，と言う感を免れません。三峡ダムは来週切り替えが始まります。ラオスのダムも何とかしてあげられませんかね。